Argentina's first lady, Cristina Fernandez de Kirchner, was on course for a landslide victory in yesterday's presidential election, according to exit polls.

The lawyer-turned-senator appeared to lead her rivals by a wide enough margin to avoid a run-off and be declared the country's first elected female head of state.

If confirmed, her victory will be as much a triumph for her husband, President Nestor Kirchner, as she ran on his record of reviving the economy after Argentina's 2001 financial meltdown.

Shortly after ballot stations closed at 7pm local time, several exit polls reported that the first lady had won 46.3% and was far ahead of her nearest rival, Elisa Carrio, who had 23.7%. She needed 40% of the vote and a lead of more than 10% over her nearest rival to win outright.

Mrs Kirchner is expected to maintain leftwing populist economic policies, such as price controls, and to inject glamour and energy into Argentine diplomacy. Her husband, dour and proudly provincial, loathed foreign trips.

One challenge will be to maintain good relations with Venezuela's President Hugo Chávez, who has poured billions of dollars into Argentina's economy, while improving ties with Washington.

Kirchner supporters did not wait for official results to start celebrating. The campaign headquarters on the 17th floor of the Intercontinental hotel in Buenos Aires soon turned into a party. Drummers bussed in from Bajo Flores, a poor district in Buenos Aires, gathered on the street outside for what promised to be a night-long fiesta.

Yesterday's apparent victory sealed a remarkable pact between the first couple.Mr Kirchner would almost certainly have won a second term after delivering rapid growth and populist policies, which most Argentines want to continue.

Instead he stepped down in favour of his wife and mobilised the Peronist machine - and state resources - behind her candidacy. There is speculation he will run again after her term, perpetuating a Kirchner dynasty.

"The president chose her because she's the best candidate," said Felipe Martinez, 39, one of the revellers outside the Kirchner headquarters. "Today we've seen that the people have put their confidence in her. We expect her to continue in the same path."

Mr Martinez was dressed as a penguin in honour of the first couple's Patagonian power base. Mr Kirchner's nickname is the Penguin. The couple's success has been dubbed March of the Penguins.

The first lady, a 54-year-old mother of two and veteran politician in her own right, evoked comparisons to Eva Peron as well as Hillary Clinton. Unlike the Democrats' frontrunner, however, she has not had to campaign hard, debate with rivals or spell out policies on inflation, crime and a looming energy crisis - serious problems which could quickly sour her presidency.

With her victory seemingly inevitable in a crowded field of 13 rivals, Mrs Kirchner's campaign had the aura of a coronation. She shunned debates with rivals, largely ignored the media and held few rallies.

"We don't know what plans she has. She hasn't said anything," said former economy minister and rival candidate Roberto Lavagna. He came third, with 13.1%, according to exit polls.

The country's 27.1 million registered voters are obliged to vote, ensuring massive turnout, but the campaign was marred by widespread apathy which gave no sense that the first election of a female president was historic. Mrs Kirchner will be the most powerful woman in Latin America since Chile's President Michelle Bachelet, the region's only other female head of state, is at the helm of a much smaller economy.

After casting her ballot in the morning Mrs Kirchner told reporters that she savoured voting because of the 1976-1983 dictatorship. "I'm part of a generation that grew up in a country in which nobody could say anything. So we value this in a very special way," she said.